The author seems to be inactive since 2007. You may take at look at:
http://forums.alliedmods.net/showthread.php?t=39755
But that is a MM Source Plugin that needs to be installed. It is not just a SourcePawn file.
However, I intend to update this plugin and fix/add some things. First of all, the plugin is vulnerable to SQL injection, as it passes all usernames and steamids to the database without escaping (especially dangerous with the argument of the !last command which every player can use. Note for myself: one should escape the following characters \,",',\r,\n,\0,%,_, at least \ and ' need to be escaped). As already requested, an option to allow only admins to make any requests would be nice (e.g. for our war server). I could also port some other features (delay to avoid spamming, showtimes, keepnames to make the database not grow to infinity) of the above mentioned plugin.
edit: I found the cause for the broken aka feature. The aka-handler explicitely searches the database for names corresponding to the steamid of the calling user (ignoring the argument of !aka). Additionally, the function uses FindTarget without loading the phrases translations (as mentioned in the API), the result however is never used.